Polyphenolic compounds are bioactive substances that are derived from plant materials and are closely associated with the sensory and nutritional quality of products containing them.
Proanthocyanidins are a class of polyphenolic compounds found in several plant species. They are oligomers of flavan-3-ol monomer units most frequently linked either as 4-6 or 4-8. The most common classes are the procyanidins which are chains of catechin, epicatechin, and their gallic acid esters and the prodelphinidins which consist of gallocatechin, epigallocatechin, and their gallic acid esters as the monomeric units. Structural variations in proanthocyanidin oligomers may also occur with the formation of a second interflavanoid bond by C—O oxidative coupling to form A-type oligomers. Due to the complexity of this conversion, A-type proanthocyanidins are not as frequently encountered in nature in comparison to the B-type oligomers.
The term “cocoa polyphenols” includes polyphenolic products including proanthocyanidins, more particularly procyanidins, extracted from cocoa beans and derivatives thereof. More specifically, the term “cocoa polyphenol” includes monomers of the formula An (where n is 1) or oligomers of the formula An (where n is an integer from 2 to 18, and higher), wherein A has the formula:

and R is 3-(α)-OH, 3-(β), 3-(α)-O-saccharide, 3-(β)-O-saccharide, 3-(α)-O—C(O)—R′, or 3-(β)-O—C(O)—R′;
bonding between adjacent monomers takes place at positions 4, 6 or 8;
a bond to a monomer in position 4 has alpha or beta stereochemistry;
X, Y and Z are selected from the group consisting of A, hydrogen, and a saccharide moiety, with the proviso that as to at least one terminal monomer, bonding of the adjacent monomer thereto is at position 4 and optionally Y═Z=hydrogen; and
wherein the saccharide moiety is a mono- or di-saccharide moiety and may be optionally substituted with a phenolic moiety and R′ may be an aryl or heteroaryl moiety optionally substituted with at least one hydroxyl group; and
salts, derivatives and oxidation products thereof.
Preferably, the saccharide moiety is derived from the group consisting of glucose, galactose, xylose, rhamnose and arabinose. The saccharide moiety and any or all of R, X, Y, and Z may optionally be substituted at any position with a phenolic moiety via an ester bond. The phenolic moiety is selected from the group consisting of caffeic, cinnamic, coumaric, ferulic, gallic, hydroxybenzoic and sinapic acids.
Proanthocyanidins have attracted increasing attention due to the rapidly growing body of evidence associating these compounds with a wide range of potential health benefits. Tea catechins have recently been associated with potent antioxidant activity and with the reduction of tumor multiplicity in laboratory mice (Lunder, 1992; Wang et al., 1992; Chung et al., 1992). Additionally, the proanthocyanidins in grape seed extracts have been shown to have free radical scavenging abilities and to decrease the susceptibility of healthy cells to toxic and carcinogenic agents (Bagchi et al., 1997; Waterhouse and Walzem, 1997; Joshi et al., 1998). Polyphenols in grape juice and red wine have been associated with potential cardiovascular benefits, including the reduction of platelet aggregation, modulation of eicosanoid synthesis and inhibition of low-density lipoprotein oxidation (Waterhouse and Walzem, 1997; Schramm et al., 1998; Frankel et al., 1995). Recently, it has been suggested that any potential health benefits attributed to these compounds may be affected by the degree of polymerization (Saito et al. 1998).
Many plant polyphenols have antioxidant activity and have an inhibitory effect on mutagenesis and carcinogenesis. For example, U.S. Pat. Nos. 5,554,645 and 5,712,305 disclose cocoa polyphenol extracts, particularly procyanidins, which have been shown to possess significant biological utility. International Publication WO 97/36497 (published Dec. 24, 1997) discloses that these extracts also function to reduce periodontal disease, arteriosclerosis and hypertension; inhibit LDL oxidation and DNA topoisomerase II; modulate cyclo-oxygenase, lipoxygenase, nitric oxide or NO-synthase, apoptosis and platelet aggregation; and possess anti-inflammatory, antigingivitis and antiperiodontis activity. Moreover, WO 97/36497 discloses that polyphenol oligomers 5-12 possess enhanced anti-cancer activity compared to the other polyphenolic compounds isolated from cocoa. Thus, consumption of these higher oligomers in cocoa products may provide significant health benefits.
As previously noted, the use of cocoa extracts or polyphenols derived there from as NO or NO-synthase modulators is described in International Publication WO 97/36497. Nitric oxide has been shown to play a role in many significant biological processes, such as neurotransmission, blood clotting, blood pressure control, regulation of serum lipid levels, cardiovascular disease, cerebral circulation (vascular headache), and a role in the immune system's ability to kill tumor cells and intracellular parasites. P. Clarkson, et al., “Oral L-arginine Improves Endothelium dependent situation in Hypercholesterolemic Young Adults”, J. Clin, Innest. 97, No 8: 1989-1994 (April 1996), P. L. Feldman, et al., “The Surprising Life of Nitric Oxide”, Chem. & Eng. News, pp. 26-38 (Dec. 20, 1993); S. H. Snyder, et al., “Biological Rules of Nitric Oxide”, Scientific American, pp. 68-77 (May 1992); P. Chowienczyk et al., “L-arginine: No More Than A Simple Amino Acid?”, Lancet, 350:901-30 (Sep. 27, 1997); M. A. Wheeler, et al., “Efforts of Long Term Oral L-Arginine on The Nitric Oxide Synthase Pathway in The Urine from Patients with Interstitial Cystitis”, J. Urology 158:2045-2050 (December 1997); A. Tenenbaum, “L-Arginine: Rediscovery in Progress”, Cardiology 90:153-159 (1998); I. K. Mohan, et al., “Effort of L-arginine Nitric Oxide System On Chemical-Induced Diabetes Mellitus”, Free Radical Biology & Medicine 25, No. 7: 757-765 (1998); S. Klahr, “The Role of L-Arginine in Hypertension and Nephrotoxicity”, Pharmacology and Therapeutics, pp. 547-550 (1998); and R. H. Boger, et al., “Dietary L-arginine and L-Tocopheral Reduce Vascular Oxidation Stress and Preserve Endothelial Function in some Hypocholesteralemic Rabbits via Different Mechanisms,” Arterosclerosis 141:31-43 (1998).
For example, health benefits from various foods have been suggested. Peanuts have been reported to be a source of resveratrol, the compound found in grapes and red wine that has been linked to reduced cardiovascular disease. A diet including walnuts has been found to result in reduced serum lipid levels and blood pressure. See Sabate, J. et al., “Effects of Walnuts on Serum Lipid Levels And Blood Pressure in Normal Men”, New England J. Med. 328:603-607 (Mar. 4, 1993). It has also been suggested that frequent consumption of nuts may offer protection from coronary heart disease. See Sabate, J. et al., “Nuts: A New Protective Food Against Coronary Heart Disease”, Lipidology 5:11-16 (1994). Without wishing to be bound by any theory, a postulated mechanism of action, among others, includes the presence of relatively high levels of arginine in nuts which results in nitric oxide production, thereby causing relaxation of vascular smooth muscle. It is believed that L-arginine is a substrate for nitric oxide production via nitric oxide synthase.
Accordingly, products, such as confectioneries and cocoa-containing products (cocoa powders, chocolate liquors, or extracts thereof) having a high cocoa polyphenol concentration, especially a high concentration of cocoa polyphenol oligomers 5-12 would be desirable. It would also be highly desirable to provide products containing effective amounts of both polyphenols, particularly the cocoa procyanidin(s), and L-arginine to stimulate the production of nitric oxide and elicit the health benefits provided therefrom.